We use a physically-based crystal plasticity model to predict the yield
strength of body centered cubic (bcc) tungsten single crystals subjected
to uniaxial loading. Our model captures the thermally-activated
character of screw dislocation motion and full non Schmid effects, both
of which are known to play critical roles in bcc plasticity. The model
uses atomistic calculations as the sole source of constitutive
information, with no parameter fitting of any kind to experimental data.
Our results are in excellent agreement with experimental measurements of
the yield stress as a function of temperature for a number of loading
orientations. The validated methodology is employed to calculate the
temperature and strain-rate dependence of the yield strength for 231
crystallographic orientations within the standard stereographic
triangle. We extract the strain-rate sensitivity of W crystals at
different temperatures, and finish with the calculation of yield
surfaces under biaxial loading conditions that can be used to define
effective yield criteria for engineering design models. (C) 2015
Elsevier Ltd. All rights reserved.